Three-dimensional electrostatic discharge semiconductor device

ABSTRACT

Three-dimensional electrostatic discharge (ESD) semiconductor devices are fabricated together with three-dimensional non-ESD semiconductor devices. For example, an ESD diode and FinFET are fabricated on the same bulk semiconductor substrate. A spacer merger technique is used in the ESD portion of a substrate to create double-width fins on which the ESD devices can be made larger to handle more current.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention generally relates to electrostatic dischargesemiconductor devices and methods of fabricating same, and moreparticularly, to double-width, three-dimensional (3D) electrostaticdischarge (ESD) semiconductor devices and common fabrication thereofwith 3D non-ESD semiconductor device(s).

2. Background Information

Semiconductor devices, such as integrated circuits, are at a risk ofdamage owing to an occurrence of overvoltages, such as electrostaticdischarge (ESD) events, typically as a result of handling by, forinstance, humans, machines or both. As the integration density ofsemiconductor devices increases and the corresponding size of circuitelements decreases, a need continues to exist for better protection ofthe semiconductor devices against such overvoltages.

SUMMARY OF THE INVENTION

The shortcomings of the prior art are overcome and additional advantagesare provided through the provision, in one aspect, of a semiconductordevice for electrostatic discharge (ESD). The device includes asemiconductor substrate, at least one raised semiconductor structurecoupled to the substrate, the at least one raised structure having awidth of about 5 nm to about 50 nm, and at least one electrostaticdischarge (ESD) semiconductor device situated at a top portion of the atleast one raised structure.

In accordance with another aspect, a semiconductor chip includes a bulksemiconductor substrate, a plurality of raised semiconductor structurescoupled to the substrate, at least one and less than all of theplurality of raised semiconductor structures having a width of about 5nm to about 50 nm. The semiconductor chip further includes a pluralityof electrostatic discharge (ESD) semiconductor devices situated at topportions of the at least one of the plurality of raised semiconductorstructures, and a plurality of at least one type of non-ESDsemiconductor device situated at top portions of a remainder of theplurality of raised semiconductor structures.

In accordance with yet another aspect, a method of creating athree-dimensional electrostatic discharge semiconductor device includesproviding a semiconductor structure, the structure including asemiconductor substrate, a blanket layer of a masking material over thesemiconductor substrate and a plurality of mandrels over the maskinglayer. The method further includes creating merged spacers between theplurality of mandrels, removing the mandrels, etching to reduce a heightof the merged spacers, etching the semiconductor substrate using thereduced height spacers as a hard mask to create raised semiconductorstructures having a width at least equal to the merged spacers, andcreating one or more ESD semiconductor devices at a top portion of atleast one of the raised structures.

These and other features and advantages of this invention will becomeapparent from the following detailed description of the various aspectsof the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional elevational view of one example of asemiconductor structure obtained at an intermediate stage offabrication, the structure including a semiconductor substrate, a masklayer disposed over the semiconductor substrate, a plurality of mandrelsover the mask layer and a spacer material conformally disposed over themandrels, in accordance with one or more aspects of the presentinvention.

FIG. 2 depicts one example of the intermediate structure of FIG. 1 withthe spacer material removed above the mandrels, in accordance with oneor more aspects of the present invention.

FIG. 3 depicts one example of the intermediate structure of FIG. 2, withthe mandrels having been removed, in accordance with one or more aspectsof the present invention.

FIG. 4 depicts one example of the intermediate structure of FIG. 3 afterpatterning of the hard mask layer, in accordance with one or moreaspects of the present invention.

FIG. 5 depicts one example of the intermediate structure of FIG. 4 afterpatterning of the semiconductor substrate to create raised semiconductorstructures, in accordance with one or more aspects of the presentinvention.

FIG. 6 depicts one example of resultant structure of FIG. 5 afterremoval of the spacer and hard mask layers, in accordance with one ormore aspects of the present invention.

FIG. 7 is a cross-sectional view of a diffused diode with multiplecontacts on a wide fin from FIG. 6, in accordance with one or moreaspects of the present invention

FIG. 8 is a cross-sectional view of a first alternate diffused diodewith additional n-well implants and multiple contacts, on a wide finfrom FIG. 6, in accordance with one or more aspects of the presentinvention.

FIG. 9 is a cross-sectional view of a second alternate diode with mergedanode-cathode implants and multiple contacts on a wide fin from FIG. 6,in accordance with one or more aspects of the present invention.

FIG. 10 is a cross-sectional view of a silicon controlled rectifierswith multiple contacts, on a wide fin from FIG. 6, in accordance withone or more aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention and certain features, advantages, anddetails thereof, are explained more fully below with reference to thenon-limiting examples illustrated in the accompanying drawings.Descriptions of well-known materials, fabrication tools, processingtechniques, etc., are omitted so as not to unnecessarily obscure theinvention in detail. It should be understood, however, that the detaileddescription and the specific examples, while indicating aspects of theinvention, are given by way of illustration only, and are not by way oflimitation. Various substitutions, modifications, additions, and/orarrangements, within the spirit and/or scope of the underlying inventiveconcepts will be apparent to those skilled in the art from thisdisclosure.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” is not limited to the precise valuespecified. In some instances, the approximating language may correspondto the precision of an instrument for measuring the value.

The terminology used herein is for the purpose of describing particularexamples only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has” and “having”), “include (and any form ofinclude, such as “includes” and “including”), and “contain” (and anyform of contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises,” “has,”“includes” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of a method or anelement of a device that “comprises,” “has,” “includes” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

As used herein, the term “connected,” when used to refer to two physicalelements, means a direct connection between the two physical elements.The term “coupled,” however, can mean a direct connection or aconnection through one or more intermediary elements.

As used herein, the terms “may” and “may be” indicate a possibility ofan occurrence within a set of circumstances; a possession of a specifiedproperty, characteristic or function; and/or qualify another verb byexpressing one or more of an ability, capability, or possibilityassociated with the qualified verb. Accordingly, usage of “may” and “maybe” indicates that a modified term is apparently appropriate, capable,or suitable for an indicated capacity, function, or usage, while takinginto account that in some circumstances the modified term may sometimesnot be appropriate, capable or suitable. For example, in somecircumstances, an event or capacity can be expected, while in othercircumstances the event or capacity cannot occur—this distinction iscaptured by the terms “may” and “may be.”

Reference is made below to the drawings, which are not drawn to scalefor ease of understanding, wherein the same reference numbers are usedthroughout different figures to designate the same or similarcomponents.

FIG. 1 is a cross-sectional elevational view of one example of anintermediate semiconductor structure obtained at an intermediate stageof fabrication of one or more semiconductor devices, in accordance withone or more aspects of the present invention. At the point offabrication depicted in FIG. 1, intermediate structure 100 includes asubstrate 102, for example, a bulk semiconductor material, e.g., a bulksilicon wafer. In one example, substrate 102 may include anysilicon-containing substrate including, but not limited to, silicon(Si), single crystal silicon, polycrystalline silicon (Poly-Si),amorphous Si, silicon-on-nothing (SON), silicon-on-insulator (SOI), orsilicon-on-replacement insulator (SRI) substrates and the like.Substrate 102 may in addition or instead include various isolations,dopings and/or device features. The substrate may include other suitableelementary semiconductors, such as, for example, germanium (Ge) incrystal, a compound semiconductor such as silicon carbide (SiC), galliumarsenide (GaAs), gallium antimondie (GaP), indium phosphide (InP),indium arsenide (InAs), and/or indium antimonide (InSb) or combinationsthereof; an alloy semiconductor including GaAsP, AlinAs, GaInAs, GaInP,or GaInAsP or combinations thereof.

Continuing with FIG. 1, a mask layer 104 is disposed over substrate 102.Mask layer 104, which may be deposited over substrate 102 using anyconventional deposition processes, such as CVD, PVD or ALD, and providesprotection to substrate 102 from damage during subsequent etchprocesses, and depending on the fabrication process, may also preventsubstrate 102 from being oxidized by exposure to an oxygen-containingenvironment. In one specific example, mask layer 104 may include anitride material, such as silicon nitride (Si₃N₄ or SiN), silicondioxide (SiO₂), SiON and the like. Although mask layer 104 may have athickness suitable to act as an etch stop layer to protect substrate 102from damage, the thickness of mask layer 104 may vary according to theprocessing node in which the semiconductor device is being fabricated.In one example, the thickness of mask layer 104 may be about 5 nm toabout 500 nm for a 14 nm technology node.

Referring still to FIG. 1, a sacrificial mandrel material 106 ispatterned over mask layer 104 to create one or more mandrels 108, e.g.,mandrels 110, 112, 114 and 115. Sacrificial mandrel material 106 may beprovided over mask layer 104 using, for instance, any conventionaldeposition processes, such as atomic layer deposition (ALD),chemical-vapor deposition (CVD), physical vapor deposition (PVD) or thelike. In one example, the sacrificial mandrel material may include amaterial such as, for example, amorphous silicon or polycrystallinesilicon. As one skilled in the art will understand, although notdepicted in figures, the patterning of the sacrificial mandrel materialmay typically include, for instance, providing an anti-reflectivecoating layer over sacrificial mandrel material 106, and providing apatterned photoresist layer over the anti-reflective layer. Thepatterning process may proceed using a desired mask pattern, to transferthe pattern from the patterned photoresist layer and to etch through thelayers, including sacrificial mandrel material 106. Note that thispatterning process may create, in one example, mandrels 110 and 112separated by a space 116 that is substantially less than the space 118separating the mandrels 114 and 115. As will be explained in more detailbelow, mandrels that are close together (e.g., mandrels 110 and 112) areassociated with the creation of one or more electrostatic discharge(ESD) semiconductor devices on a same substrate (here, same wafer) asone or more non-ESD semiconductor devices, with which the farther-spacedmandrels (e.g., mandrels 114 and 115) are associated. In other words,fins subsequently created from the more closely spaced mandrels willhave ESD devices at a top portion thereof, while non-ESD devices (e.g.,FinFETs) will be created on fins fabricated using the more spacedmandrels.

Continuing further with FIG. 1, a sidewall spacer material 120 isconformally deposited over mandrels 108. Sidewall spacer material 120may include, for instance, an oxide material such as, for example,silicon oxide (SiO₂), which may be conformally deposited using a varietyof techniques, such as, for example, chemical vapor deposition (CVD) oratomic layer deposition (ALD). Note that sidewall spacer material 120may be disposed over and along the sidewalls of mandrels 108.

As depicted in FIG. 2, the sidewall spacer material is removed fromabove the mandrels (see FIG. 1), for instance, by etching using anyappropriate non-selective etching processes, to form sidewall spacers124, e.g., spacers 126, 127, 128 and 129. In one example, anon-selective chemical mechanical polish may be performed to remove thesidewall spacer material from above the mandrels, while leaving it alongthe sidewalls of the mandrels. Note that between the more closely spacedmandrels, the sidewall spacer material creates a merged spacer 126within the space 116 (see FIG. 1) separating the mandrels and unmergedspacers 127, 128 and 129. The merged aspect of the spacersadvantageously facilitate in doubling their width, and, hence,increasing the width of resulting fins, as described below. In addition,the increased width decreases the distance (also referred to as pitch,as understood in the art) between two merged spacers as compared tounmerged spacers, during subsequent processing. Etching the sidewallspacer material from above the mandrels (see FIG. 1) results in exposingunderlying sacrificial mandrel material 106.

As illustrated in FIG. 3, exposed sacrificial mandrel material 106 (seeFIG. 2) is subsequently etched, using a selective etch processing,resulting in exposing underlying mask layer 104, while leaving sidewallspacers that may be used as a hard mask during subsequent processing.The selective etch process may be one or more anisotropic, dry-etchprocesses, such as, for example, oxygen strip or plasma etchingprocessing. As discussed above, the hard mask includes merged spacer 126having a width that is substantially greater than the width of unmergedspacers 127 and 128. In a specific example, the width of merged spacer126 may be approximately two times the width of unmerged spacers 127 and128.

As illustrated in FIG. 4, mask layer 104 (see FIG. 3) may be patternedusing the sidewall spacers to create a mask pattern 130. This maskpattern 130 may then be used in patterning underlying semiconductorsubstrate 102 to create fins, or, more generally, raised semiconductorstructures. Any conventional anisotropic dry-etching processes such as,reactive ion etching or plasma etching may be performed to etch throughmask layer 104 and to create the mask pattern. In a specific example,reactive ion etching may be performed using remote plasma involvingprocess gases such as nitrogen trifluoride (NF₃) and hydrogen (H₂). Inanother example, anisotropic dry etching process, such as reactive ionetching using fluorine-based chemistry involving process gases such astetrafluoromethane (CF₄), trifluoromethane (CHF₃), sulfur hexafluoride(SF₆) may be employed.

One or more etching processes may be performed to selectively pattern aportion of semiconductor substrate 102 using mask pattern 130 and thesidewall spacers, as depicted in FIG. 5, to create one or more raisedstructures 132, e.g., raised structures 134 and 136, separated by aspace 138. Note that the resulting one or more raised structures 132such as, for example, semiconductor fins, are coupled to a portion ofsemiconductor substrate 102. Note also that, there exists a widthvariation between raised structure 134 and raised structure 136,resulting from width variations caused by merged spacers 126 andunmerged spacers 127 and 128. Further, the width of raised structure 134and raised structure 136 is at least equal to (and gradually downward,larger than) the width of merged spacers 126 and unmerged spacers 127and 128, respectively.

In a specific example, the width of raised structure 134, beingapproximately equal to the width of merged spacers 126 at a top portion135 thereof and gradually getting larger at a base 137, may be in therange of about 10 nanometers to about 40 nanometers, while the width ofraised structures 136, dictated by unmerged spacer 127, may be in therange of about 5 nanometers to about 30 nanometers.

As shown in FIG. 6, a non-selective chemical-mechanical polish ornon-selective etching may be employed to remove the remaining portion ofthe sidewall spacers (see FIG. 4) and remaining portions of mask pattern130 (see FIG. 4) overlying raised structures 132. As understood,“non-selective” in this context means that the polish rate or etch rateis close between the sidewall spacers of FIG. 4 and the mask pattern ofFIG. 4, which in one example, are an oxide and nitride materials,respectively. Note that this non-selective removal processes, e.g.,non-selective chemical-mechanical polish or non-selective etchingprocesses result in creating at least one or more wider raisedstructures 133 and at least one or more standard width raised structures135, on the same semiconductor wafer.

The present invention proceeds to create one or more electrostaticdischarge (ESD) devices over the top portion of at least one of thewider raised structures 133, for example, over the top portion of raisedstructure 134. The fabrication of an electrostatic discharge (ESD)device over the top portion of raised structure 134 provides a largerwidth as compared to the more standard width of raised structures 135,e.g., raised structure 136, advantageously facilitating in handling alarger electrostatic discharge (ESD) current as compared to anelectrostatic discharge (ESD) current that could be handled by an ESDdevice on one of the standard width raised structures 135. Electrostaticdischarge (ESD) devices may include, for example, a diode, a bipolarjunction transistor (BJT) and a silicon controlled rectifier (SCR), withthe simplest of those structurally being, of course, a diode. BJTs andSCRs are best suited for high voltage situations, while diodes are bestsuited to large current transients, due to their fast turn-on. Thus, thefollowing example uses diodes in order to simplify the description andresulting understanding of the invention.

As depicted in FIG. 7, diodes may be formed on three-dimensional (3D)semiconductor structures, such as, for example, fins similar to thoseused with FinFETs. Diode 140 includes a well 142 at a top of one or morewider raised structures, for example, raised structure 134 from FIG. 6,the well including either a p-type dopant or an n-type dopant, dependingon the conductivity type-PNP or NPN- of the diode. In addition, it willbe understood that such a diode can be used in forward biased, reversebiased or circuits mode. In a specific example, well 142 has an n-typedopant, and includes an anode implant (AI) 144, the anode implant 144being of opposite type than the n-type well 142, and a cathode implant(CI) 146, the cathode implant 146 being the same type as n-type well142. Note that the depth of the anode implant (AI) and the cathodeimplant (CI) may be substantially deeper than conventional source anddrain implants. In one example, the depth of anode implant (AI) 144 andcathode implant (CI) 146 may be in the range of about 0.2 μm to about 2μm. Note that the increased depth of such a diode 140, advantageously,facilitates in handling more current with low on-resistance (R_(on)).The fabrication may further proceed to create gate structure 147 andmultiple contacts 148, for example, contacts 150 and 152 to improvecurrent handling. In one example, contact 150 may be electricallycoupled to anode implant (AI) 144, whereas contact 152 may beelectrically coupled to cathode implant 146, to further improve currenthandling. Multiple contacts 148, in one example, may include a silicide151, such as, for example, nickel silicide, titanium silicide, platinumsilicide and the like. Note that in this implementation, theconventional semiconductor fins may be placed parallel or perpendicularto the diode junction boundary; in this case, the boundary 153 isperpendicular to fin 134. Although not critical to the invention, eachof these diodes may be separated by isolation features, such as, forexample, shallow trench isolation features 143.

Alternately, as depicted in FIG. 8, each of the diodes, e.g., diode 160,may also include a well 162 in the at least one wider raised structure,for example, raised structure 134 from FIG. 6, the well including eithera p-type dopant or an n-type dopant, depending on the conductivitytype-PNP or NPN- of the diode. In a specific example, first well 162 hasa p-type dopant, and includes an anode implant (AI) 164, the anodeimplant 164 being of a same type as the p-type well 162. First well 162may also include a second well 166 within, for instance, the p-type well162. In such a case, second well 166 may be of opposite type than thefirst well 162, and a cathode implant (CI) 168 may be disposed withinsecond well 166, the cathode implant 146 being the same type as secondwell 166. Note that, in this implementation, the diode junction area isformed by the boundary of second well 166 to first well 162, and thatthe area of the diode may be altered to attain low on-resistance(R_(on)). Note also that the conventional semiconductor fins may beplaced parallel or perpendicular to the diode junction boundary (in thiscase being perpendicular). The fabrication may further proceed to createthe gate structure and multiple contacts 170, for example, contacts 172and 174 to improve current handling. In one example, contact 172 may beelectrically coupled to anode implant (AI) 164, whereas contact 174 maybe electrically coupled to second well 166 via cathode implant 168, tofurther improve current handling. Multiple contacts 170, in one example,may include a silicide such as, for example, nickel silicide, titaniumsilicide, platinum silicide and the like.

In yet another alternate implementation, as illustrated in FIG. 9, eachdiode 176 may include a well 178 in the at least one wider raisedstructure, for example, raised structure 134 from FIG. 6, the wellincluding either a p-type dopant or an n-type dopant, depending on theconductivity type-PNP or NPN- of the diode. In a specific example, well178 has an n-type dopant, and includes an anode implant (AI) 180, theanode implant being the opposite type as the n-type well 178, and acathode implant (CI) 182, the cathode implant being of the same type asn-type well 178. In this implementation, anode implant (AI) 180 andcathode implant (CI) 182 are extended toward each other, as compared tothe examples above, such that the anode implant and the cathode implantmay be merged with each other to form a highly doped junction region183, the highly doped junction region being capable of acting as a Zenerdiode under reverse bias conditions. One skilled in the art will notethat, such a diode can provide a low reverse biased resistance to anelectrostatic discharge (ESD) event. In one example, the depth of anodeimplant (AI) 180 and cathode implant (CI) 182 may be in the range ofabout 0.05 μm to about 3 μm. The fabrication may further proceed tocreate the gate structure and multiple contacts 184, for example,contacts 186 and 188, to improve current handling. In one example,contact 186 may be electrically coupled to anode implant (AI) 180,whereas contact 188 may be electrically coupled to cathode implant 182,to further improve current handling. Multiple contacts 184, in oneexample, may include a silicide such as, for example, nickel silicide,titanium silicide, platinum silicide and the like.

In yet another example, Silicon Controlled Rectifiers (SCRs) serve asESD devices, and are also be fabricated over at least one wider raisedstructure, e.g., raised structure 134 from FIG. 6. In one example, asillustrated in FIG. 10, Silicon Controlled Rectifier (SCR) 189 includesa diode 190, each of the diode including a first well 192, a second well194 and third well 200, in the at least one wider raised structure, forexample, raised structure 134 from FIG. 6, each of the first well, thesecond well and the third well including either a p-type dopant or ann-type dopant, depending on the conductivity type-NPNP or PNPN- of theSCR. First well 192 and third well 200 are both of the same type (n-typeor p-type), while middle well 194 is either a well of the opposite typeor simply a substrate of the opposite type. A first junction 195 liesbetween first well 192 and implant 196. In a specific example, firstwell 192 has an n-type dopant and anode implant (AI) 196 is p-type,i.e., of opposite type to first well 192, and adjacent second well 194has a p-type dopant and includes an anode implant (AI) 198 that is asame type as second well 194. Further, a third well 200 is disposedadjacent to second well 194, the third well having an n-type dopant anda cathode implant (CI) 202 that is of the same type as the third well200. A second junction 197 is situated between second well (or p-typesubstrate) 194 and third well 200.

Optionally, the anode and cathode implants may be deep, as described inprior examples, though not merged, and the orientation of the raisedstructures may be parallel or perpendicular to the junction boundaries(here, the raised structure is perpendicular to the junctions). Thefabrication may further proceed to create the gate structure andmultiple contacts 204, for example, contacts 206, 208 and 210, toimprove current handling and optimize the parasitic bipolar aspect (withcontact 208). In one example, contact 206 may be electrically coupled toanode implant (AI) 196, contact 208 may be electrically coupled tosecond anode implant 198 and contact 210 may be electrically coupled tocathode implant 202, to further improve current handling. Multiplecontacts 204, in one example, may include a silicide such as, forexample, nickel silicide, titanium silicide, platinum silicide and thelike.

While several aspects of the present invention have been described anddepicted herein, alternative aspects may be effected by those skilled inthe art to accomplish the same objectives. Accordingly, it is intendedby the appended claims to cover all such alternative aspects as fallwithin the true spirit and scope of the invention.

1. A semiconductor device, comprising: a semiconductor substrate; atleast one raised semiconductor structure coupled to the substrate, theat least one raised structure having a width of about 5 nm to about 50nm; and at least one electrostatic discharge (ESD) semiconductor devicesituated at a top portion of the at least one raised structure.
 2. Thesemiconductor device of claim 1, wherein the at least one ESD devicecomprises a diode.
 3. The semiconductor device of claim 2, furthercomprising a plurality of current-handling contacts electrically coupledto the diode.
 4. The semiconductor device of claim 3, wherein thesubstrate and the at least one raised structure comprise silicon, andwherein the plurality of current-handling contacts comprise a silicide.5. The semiconductor device of claim 4, wherein the silicide comprisesone of nickel silicide, titanium silicide, and platinum silicide.
 6. Thesemiconductor device of claim 2, wherein the diode comprises: a well inthe at least one raised structure, wherein the well is one of n-type andp-type; an anode of a type opposite the well and having a depth in thewell of about 0.05 μm to about 3 μm; a cathode of a same type as thewell and having a depth in the well of about 0.05 μm to about 3 μm; atleast one contact electrically coupled to the anode; and at least oneother contact electrically coupled to the cathode.
 7. The semiconductordevice of claim 6, wherein the anode and the cathode are merged at ajunction thereof.
 8. The semiconductor device of claim 2, wherein thediode comprises: an anode of p-type or n-type; a first well of a typeopposite the anode; a cathode in the first well of a same type as thefirst well; at least one contact electrically coupled to the anode; andat least one other contact electrically coupled to the cathode.
 9. Thesemiconductor device of claim 8, further comprising a second well of asame type as the anode, wherein the second well encompasses the anode,the first well and the cathode.
 10. The semiconductor device of claim 8,wherein the substrate is of a same type as the anode.
 11. Thesemiconductor device of claim 1, wherein the ESD device comprises abipolar junction transistor.
 12. The semiconductor device of claim 1,wherein the ESD device comprises a silicon controlled rectifier.
 13. Asemiconductor chip, comprising: a bulk semiconductor substrate; aplurality of raised semiconductor structures coupled to the substrate,at least one and less than all of the plurality of raised semiconductorstructures having a width of about 5 nm to about 50 nm; a plurality ofelectrostatic discharge (ESD) semiconductor devices situated at topportions of the at least one of the plurality of raised semiconductorstructures; and a plurality of at least one type of non-ESDsemiconductor device situated at top portions of a remainder of theplurality of raised semiconductor structures.
 14. The semiconductor chipof claim 13, wherein the plurality of ESD devices comprises at least oneof a diode and a bipolar junction transistor.
 15. A method, comprising:providing a semiconductor structure, the structure comprising asemiconductor substrate, a blanket layer of a protective material overthe semiconductor substrate and a plurality of mandrels over theprotective layer; creating merged spacers between the plurality ofmandrels; removing the mandrels; etching to reduce a height of themerged spacers; etching the semiconductor substrate using the reducedheight spacers as a hard mask to create raised semiconductor structureshaving a width at least equal to the merged spacers; and creating one ormore ESD semiconductor devices at a top portion of at least one of theraised structures.
 16. The method of claim 15, wherein the protectivelayer comprises one of SiN, SiO₂ and SiON, and wherein the mandrelscomprise one of amorphous silicon and polycrystalline silicon.
 17. Themethod of claim 15, wherein the mandrels are spaced to encourage spacermerger, and wherein creating the merged spacers comprises conformallydepositing a spacer material over the mandrels.
 18. The method of claim15, wherein removing the mandrels comprises: etching the spacer materialto expose the mandrels; and etching to remove the exposed mandrels. 19.The method of claim 15 wherein etching to create the raised structurescomprises: etching the protective layer to remove the protectivematerial between the reduced height spacers; etching the substrate tocreate the raised structures; removing the reduced height spacers; andremoving the protective material on the raised structures.
 20. Themethod of claim 15, wherein the semiconductor substrate comprises a bulksemiconductor substrate, wherein the structure comprises at least oneESD region and at least one non-ESD region, the non-ESD region for oneor more non-ESD semiconductor devices, and wherein the merged spacersare created in the at least one ESD region.